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Resistor for wig wag flasher unit

K

Kato's 8

Well Known Member
Hello all,
I bought a simple flasher module from B&C and instructions call for a 75ohm 2 watt resistor to be used if led or hid lamps are used. I am using a hid landing light so I went to radio shack for this resistor. They don't have it of course. So I have questions. First, will a 1 watt 100 ohm resistor work? And two, why does the duck works hid lamp require one in the first place?
Thanks!
 
Kato's 8 said:
instructions call for a 75ohm 2 watt resistor

will a 1 watt 100 ohm resistor work?

And two, why does the duck works hid lamp require one in the first place?
Thanks!
Click to expand...

The gents that made the instructions probably knew what they were doing.
I suggest following them.

The 75 ohm resistor specified will be loaded to approx 2 watts so the power callout is appropriate.

A 100 ohm would be approx 1.5 watts so a 1 watt is too small. Secondarily, it will allow less current to pass. I imagine there is a particular current needed (as would be inherent in an incandescent bulb and not replicated by LED and HID power supplies) for the flasher for it to do the switching. Bimetalic beam switches work on this principle although this unit could be solid state. The reduced current passed by the 100 ohm may not allow the flasher to work.
 
What Bill said.

It is OK to get a resistor that has a HIGHER wattage rating but do not get one that has a lower wattage rating. Lower wattage rating will get HOT and may burn up like a fuse. A higher wattage rating will be cooler, larger in size, but still work.

Here is a link to a vendor that sales what you spec.
http://www.vetco.net/catalog/product_info.php?products_id=8610

Link to 75 Ohm 5 Watt Resistor.
http://www.vetco.net/catalog/product_info.php?products_id=9773&keywords=75 ohm 5 watt resistor
 
Use 2 resistors in parallel

The previous posters are all correct, hover, you could use 2 1-watt resistors in parallel. Putting 2 150 ohm resistors in parallel will yield a 75 ohm resistance as seen by the circuit. Since they are in parallel, they each take half the current, so each of them could be 1 watt. Of course, this does add weight, but this is a solution that you could accomplish locally.

I am guessing that the resistor limits in rush current, but am not certain.

Send me a PM if you need further details.

David
 
Kato's 8 said:
And two, why does the duck works hid lamp require one in the first place?
Thanks!
Click to expand...

It is not the DW HID lamp that requires the resistor, it is the flasher unit that requires it when using the lower current lights like HID or LED. Picky distinction, but helps to understand how the system works. The resistors help load the flasher.

My guess is the flasher unit is using bi-metal switching or something functionally similar. Bi-metal strips bend in use, due to the heat generated by a high enough current going through them, and the bending action opens up a set of contact points. It is the open and closing of these contacts that make the wig and wag.

http://en.wikipedia.org/wiki/Bimetallic_strip
 
Hi Bill,

I just installed the BNC flasher with the resistors using HID (55watt) lamps. It works well but the resistors get pretty hot. You do not want to go down in wattage rating. Also, when installing the resistors, do not use any shrinkwrap over them to make a nice secure joint as the heat cannot get out fast enough.

I found the resistors online, and bought a bunch. Surprisingly, BNC doesn't sell them. Personally, I think they should include them with each flasher. Send me your address and I'll send you some.

Bevan
 
Last edited:
Lower the resistor value, up the Watts

Bill,
I have had a lot of experience with this SSF-1 flasher from B&C. We have been using it in our panel builds for years. With the HID and LED's becoming so popular we began seeing issues using these flashers. They utilize the ground path thru the lamps filiment to WigWag. Although sold thru B&C this flasher was designed by Bob Nuckolls. He came up with the 75 ohm,2 Watt resistor to simulate the path to ground to activate the flasher. I have had problems with this value being low enough for the flasher to actually work. Last week I gave Bob a call and discussed this with him. We agreed on 50 ohm 10Watt was a better setup. The 75ohm 2 Watt just gets too hot and sometimes just won't cut it. I'd suggest verifying this with him if you are at all concerned, however this has been working for us.

Jason Smith
Aerotronics Inc.
 
WigWag with BD Squadron Pro lights

Jason said:
Bill,
I have had a lot of experience with this SSF-1 flasher from B&C. We have been using it in our panel builds for years. With the HID and LED's becoming so popular we began seeing issues using these flashers. They utilize the ground path thru the lamps filiment to WigWag. Although sold thru B&C this flasher was designed by Bob Nuckolls. He came up with the 75 ohm,2 Watt resistor to simulate the path to ground to activate the flasher. I have had problems with this value being low enough for the flasher to actually work. Last week I gave Bob a call and discussed this with him. We agreed on 50 ohm 10Watt was a better setup. The 75ohm 2 Watt just gets too hot and sometimes just won't cut it. I'd suggest verifying this with him if you are at all concerned, however this has been working for us.

Jason Smith
Aerotronics Inc.
Click to expand...

To update an old thread - I'm using the Knuckolls designed wigwag circuit with a pair of Baja Designs 4300 lumen LED lights in Duckworks mounts. B&C doesn't seem to sell the flasher anymore. It is available at various places online. Search for Tridon EL 13A2 I was unable to get the lights to flash using his 75 ohm, 5w callout. I paralleled the resistors for 37.5 ohms and got solid flashing for the 20 minutes that I ran it. The resistors get too hot to grip between fingers but not too hot to touch lightly. I think it's a go. For the purists who think that it's a lot of wasted amperage, it calcs out to about a third of an amp on top of the 3.5a (measured) that the LED draws. That's not so much compared to the 100w halogens at 8 amps. I might buy some 50 ohm, 10w resistors to try out and save maybe a tenth of an amp, and likely run a little cooler.

Ed Holyoke
 
Bicyclops said:
To update an old thread - I'm using the Knuckolls designed wigwag circuit with a pair of Baja Designs 4300 lumen LED lights in Duckworks mounts. B&C doesn't seem to sell the flasher anymore. It is available at various places online. Search for Tridon EL 13A2 I was unable to get the lights to flash using his 75 ohm, 5w callout. I paralleled the resistors for 37.5 ohms and got solid flashing for the 20 minutes that I ran it. The resistors get too hot to grip between fingers but not too hot to touch lightly. I think it's a go. For the purists who think that it's a lot of wasted amperage, it calcs out to about a third of an amp on top of the 3.5a (measured) that the LED draws. That's not so much compared to the 100w halogens at 8 amps. I might buy some 50 ohm, 10w resistors to try out and save maybe a tenth of an amp, and likely run a little cooler.

Ed Holyoke
Click to expand...

I am using that same flasher (from amazon) with my Baja lights and resistors are not required if wired properly. this type of flasher, unlike traditional alternating flashers, does not use current to the light to activate the coil (most use a coil and not bi-metallic springs). It has a timer IC and transistor. It starts alternating as soon as you put 12 volts on the "X" input. You don't want the resistors if you don't need them, as they increase your current draw and produce heat.

Edit: I apologize, it was the EL13A2 that I replaced. It was a CEC X000S6CHHB flasher that operates as I describe above. The EL13 would require resistors.

Larry
 
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Another option is to use either of these wig-wag flashers that are solid state and don't care about the loads if you go to lower power LED lamps. They do need an inrush limiter for lamps over 85W though -

http://www.periheliondesign.com/wigwagdmnl.htm

http://www.periheliondesign.com/wigwagmnl.htm

It is small enough to just clamp right behind the lighting switches on my panel -

wwc_art.JPG
 
Still working to find the right resistance

Copy that Larry. I might try that flasher. My circuit has the flasher wired hot and the outputs switched per the 2 switch Aeroelectric drawing. Is the thing going to be clicking all the time if it isn't switched to a light? If it will flash one light at a time I'd have turn signals. That might come in handy for the occasional head on on the taxiway. ;-)

So, I had success with a pair of 75ohm 5w resistors in parallel on each side. Resistors ran kinda warm, but it did operate for 20 minutes with no hiccups. Then I went with 50ohm 10w and it works for about 2 minutes and then hangs and buzzes the flasher. I think the sweet spot is somewhere around 40ohms. That works out to .36 amps and about 5w.

Ed

lr172 said:
I am using that same flasher (from amazon) with my Baja lights and resistors are not required if wired properly. this type of flasher, unlike traditional alternating flashers, does not use current to the light to activate the coil (most use a coil and not bi-metallic springs). It has a timer IC and transistor. It starts alternating as soon as you put 12 volts on the "X" input. You don't want the resistors if you don't need them, as they increase your current draw and produce heat.

Edit: I apologize, it was the EL13A2 that I replaced. It was a CEC X000S6CHHB flasher that operates as I describe above. The EL13 would require resistors.

Larry
Click to expand...
 
Panel is already marked

Howdy Gil,

Already silkscreened my panel for 2 switches with w/w in the center position. Don't want to change that now.

Ed

az_gila said:
Another option is to use either of these wig-wag flashers that are solid state and don't care about the loads if you go to lower power LED lamps. They do need an inrush limiter for lamps over 85W though -

http://www.periheliondesign.com/wigwagdmnl.htm

http://www.periheliondesign.com/wigwagmnl.htm

It is small enough to just clamp right behind the lighting switches on my panel -

wwc_art.JPG
Click to expand...
 
Bicyclops said:
Copy that Larry. I might try that flasher. My circuit has the flasher wired hot and the outputs switched per the 2 switch Aeroelectric drawing. Is the thing going to be clicking all the time if it isn't switched to a light? If it will flash one light at a time I'd have turn signals. That might come in handy for the occasional head on on the taxiway. ;-)

So, I had success with a pair of 75ohm 5w resistors in parallel on each side. Resistors ran kinda warm, but it did operate for 20 minutes with no hiccups. Then I went with 50ohm 10w and it works for about 2 minutes and then hangs and buzzes the flasher. I think the sweet spot is somewhere around 40ohms. That works out to .36 amps and about 5w.

Ed
Click to expand...

Yes, the X input has to be switched. My original setup was the same as yours and I was able to come up a with a wiring plan that still worked with the DPDT switch. Let me know if you want a wiring diagram to make it work. Heat wasn't the big issue for me, it was the extra current draw. The primary point of LED for me was to get the current demand down.

Larry
 
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